The biological approach to explaining and treating OCD

Question 1

In what 2 ways does the biological approach explain OCD?

Answer 1

Genetic explanations

Neural explanations

Question 2

What is included in genetic explanations?

Answer 2

• Family history / genetics
• Diathesis Stress
• Candidate genes
• OCD is polygenic
• Different types of OCD

Question 3

What is included in neural explanations?

Answer 3

• Low serotonin
• Basal Ganglia
• Decision making systems (left parahippocampal Gyrus)

Question 4

How does family history / genetics lead to OCD?

Answer 4

The genetic explanation suggests that whether a person develops develops OCD is at least partly due to their genes.

Lewis (1936) of his OCD patients:
- 37% had parents with OCD
- 21% had siblings with OCD
COULD BE A GENETIC LINK BUT MOST LIKELY PASSING ON A GENETIC VULNERABILITY

Question 5

How does stress diathesis lead to OCD?

Answer 5

Suggests that people gain a vulnerability through genes but an environmental stressor is also required e.g. bereavement.

Question 6

How do Candidate Genes lead to OCD?

Answer 6

They create vulnerability to OCD.

Question 7

What are the 2 types of candidate genes?

Answer 7

1. COMT gene

2. SERT gene

Question 8

How does the COMT gene lead to OCD?

Answer 8

Regulates the amount of the neurotransmitter dopamine in the brain. This gene causes low levels of enzyme which means high levels of dopamine = OCD.

Question 9

What is dopamine?

Answer 9

Pleasure neurotransmitter. It is involved in causing feelings of pleasure, addiction, movement and motivation.

Question 10

What is serotonin?

Answer 10

A mood neurotransmitter. It produces feelings of well-being, happiness and helps sleep cycle and digestive system regulation.

Question 11

How does the SERT gene lead to OCD?

Answer 11

The SERT gene creates a protein which removes serotonin and recycles it. If the gene creates too much of the protein, serotonin levels decrease. Low serotonin levels = OCD.

Question 12

Explain the role of serotonin and how it links to OCD (neural explanation)

Answer 12

Serotonin is a neurotransmitter which is believed to help regulate mood. Neurotransmitters are responsible for relaying info from one neuron to another. If a person has low levels of serotonin then normal transmission of mood-relevant info doesn’t take place and a person may experience low moods (and other mental processes may be affected).

Question 13

Why does low levels of serotonin lead to OCD

Answer 13

Low levels of serotonin = abnormal transmission of mood-relevant information. Mood and perhaps other mental processes are affected.

Question 14

What is the Basal Ganglia?

Answer 14

Region of the brain involved in the coordination of movement (motor control) that has been linked to OCD.

Question 15

How does the Basal Ganglia lead to OCD?

Answer 15

Hypersensitivity gives a rise to the repetitive motor behaviours seen in OCD, for example repetitive washing/cleaning/checking.

Question 16

How does decision making systems lead to OCD?

Answer 16

Some cases of OCD seem to be associated with impaired decision-making. This in turn may be associated with abnormal functioning of the lateral of the frontal lobes of the brain. There is also evidence of the left parahippocampal gyrus functioning abnormally in OCD.

Question 17

What are the frontal lobes responsible for?

Answer 17

The frontal lobes are the front part of the brain that are responsible for logical thinking and making decisions.

Question 18

What is the left parahippocampal gyrus associated with?

Answer 18

Associated with processing unpleasant emotions - functions abnormally in OCD.

Question 19

How does the biological approach treat OCD?

Answer 19

Drug Therapy

Question 20

What types of Drug Therapy does the biological approach use to treat OCD?

Answer 20

• SSRIs [selective serotonin reuptake inhibitors]
• Combining SSRIs with other treatment
• Alternatives to SSRIs

Question 21

What is drug therapy?

Answer 21

Treatment involving drugs i.e. chemicals that have a particular effect on the functioning of the brain or some other body system. In the case of psychological disorders such drugs usually affect neurotransmitter levels.

Question 22

Describe what drug therapy for mental disorders does

Answer 22

Drug therapy for mental disorders aims to increase or decrease levels of neurotransmitters in the brain or to increase/decrease their activity. E.g. drugs to treat OCD work in various ways to increase the level of serotonin on the brain.

Question 23

What are SSRIs?

Answer 23

Selective serotonin reuptake inhibitors are a particular type of antidepressant that work on the serotonin system in the brain.

Question 24

Explain how SSRIs treat OCD using technical terms

Answer 24

• Serotonin is released by the presynaptic neurons and travels across a synapse.
• The neurotransmitter chemically conveys the signal from the presynaptic neuron to the postsynaptic neuron and then it’s reabsorbed by the presynaptic neuron when it is broken down and reused.
• By preventing the reabsorption and breakdown, SSRIs effectively increase levels of serotonin in the synapse and thus continue to stimulate the postsynaptic neuron. This compensates for whatever is wrong with the serotonin system in OCD.

Question 25

Describe the dosage of SSRIs

Answer 25

• The drug is available as capsules or liquid.

* It takes 3-4 months of daily use to have much impact on symptoms

Question 26

How are SSRIs combined with other treatment to treat OCD?

Answer 26

Drugs are often used alongside cognitive behaviour therapy to treat OCD.
• The drugs reduce a person’s emotional symptons (feeling anxious/depressed).
• This means the patient can engage more effectively with the CBT.

Question 27

What are the alternatives to SSRIs?

Answer 27

• The dose can be increased if the SSRI isn’t effective after 3-4 months or it can be combined wih other drugs.
• Tricylics can be used
• SNRIs (serotonin-noradrenaline reuptake inhibitors)

Question 28

What are Tricyclics?

Answer 28

An older type of antidepressant such as clomipramine. It has the same effect on the serotonin system as SSRIs. However it has more side-effects than SSRIs so it is generally kept in reserve for people who don’t respond to SSRIs.

Question 29

What are SRNIs?

Answer 29

They are a different class of anti-depressant drugs and a second line of defence for people who don’t respond to SSRIs. SNRIs increase levels of serotonin as well as noradrenaline (another neurotransmitter).